KOF – BOF – TOC – Heavy metals and Nutrient salts

KOF and BOF

Chemical Oxygen Demand (COD) is an important parameter used to assess water quality.
It quantifies the amount of dissolved oxygen required to chemically break down organic materials in water, such as petroleum compounds.
Definition: COD represents the oxygen demand needed to oxidize all materials present in a water sample.
Unlike BOF, Biological Oxygen Demand, or in English “Biochemical Oxygen Demand” (BOD), which measures the oxygen consumed by bacteria over a 5-day period, KOF focuses on the chemical oxidation of all substances.
While both KOF and BOF estimate different levels of contamination, they serve different purposes: KOF measures the chemical degradation of pollutants. BOF indicates the biological degradation of organic pollutants by microorganisms. There is a correlation between KOF and BOF, but it must be established experimentally before using one parameter to express the other. Typically, KOF analysis (which is faster and more accurate) is used to estimate BOF based on this correlation.
High COD levels in wastewater indicate concentrations of organic substances that can deplete dissolved oxygen in water, leading to negative environmental consequences (fish kills, for example).
Monitoring KOF helps determine the impact of organic pollution and ensures compliance with wastewater oxygen demand regulations. It is important during municipal and industrial wastewater treatment to evaluate treatment efficiency and reduce organic loading before water is discharged to the recipient.

TOC

All organic molecules contain carbon: Total organic carbon (TOC) is a measure of the concentration of organic carbon in a substance and is considered to be the best indicator of the contamination, or purity, of a substance.
Measuring TOC in process water enables companies across a range of industries to know whether the water they use is clean enough for their processes and purposes, and will not cause health or environmental harm. An example of TOC measurement is monitoring the production of infusion fluids in the pharmaceutical industry.

For continuous measurement, we can supply instruments that measure with UV absorbance technology. These provide so-called "equivalent" CODeq, BODeq, TOCeq values, which are not as accurate as lab analyses, but still provide continuous instantaneous values that indicate well how the organic content in the sample is doing, and that no reagents are required to perform the measurements.
We can also supply laboratory and portable instruments that follow internationally approved measurement methods.

Heavy metals and nutritional salts

Heavy metals are considered metallic elements with a density higher than 5 g/cm³, which means at least 5 times greater density than water.
Examples of elements that belong to this group are copper (Cu), chromium (Cr), mercury (Hg), nickel (Ni), iron (Fe) and zinc (Zn).
Since these are elements, they cannot be broken down, and can therefore accumulate to undesirable levels in nature due to excessive emissions from various industries. Via the food chain, the elements also find their way into animals and thus to us humans.

To measure heavy metal load, well-known lab methods are used within the principles of photometric and colorimetric, titration and ion-selective. We supply equipment that uses these measurement techniques.